1. Technical Field
The present invention relates generally to telephone networks and the Internet; and more particularly to the routing of telephone calls within a telephone network to proximately located or preferred gateways that couple the telephone network to the Internet.
2. Related Art
The structure of modern telephone networks often includes a traffic network and a coupled signaling network. The traffic network includes a plurality of switches interconnected by traffic handling trunks. Many of these switches serve as central office switches that couple to a plurality of terminals as well as to other of the plurality of switches. The signaling network interfaces with the traffic network to perform call routing and management functions.
In an example of the manner in which a telephone network services a call, a switch (origination switch) receives a request from a calling terminal that includes a Dialed Number, the calling terminal requesting that the call be completed to a called terminal (associated with the Dialed Number) that is coupled to another switch (destination switch). The origination switch initiates call set up by interacting with the signaling network and requesting that the call be set up and routed to the called terminal (associated with the Dialed Number). During call set up, the origination switch transmits the Dialed Number to the signaling network in a origination message. The signaling network then routes the origination message to a destination switch. The destination switch then attempts to allocate a traffic trunk back to the originating switch. If the allocation is successful, the destination switch notifies the originating switch of such allocation via the signaling network and completes the call to the called terminal (if available).
Typical public Internet access currently includes linking a call from a subscriber to its Internet service provider (ISP) via the telephone network. In linking the call, the subscriber employs his or her modem to dial the number of a modem bank of the service provider. The call is set up via the telephone network and terminated to the modem bank. An Internet protocol gateway operated by the ISP coupled to the modem bank then sets up a data session with the subscriber""s computer which is coupled to the subscriber""s modem, such session set up is provided across the telephone network. With the session established, access to the Internet is then provided.
Many Internet service providers establish multiple modem banks, each of which couples to the telephone network at a corresponding location. For example, a large Internet service provider may include modem banks in the cities of Dallas, Richardson, Arlington, Fort Worth and other cities in the greater Dallas area. These modem banks allow most users to access the Internet service provider via a local phone call. However, most Internet service providers limit the access to each of these modem banks to locally registered subscribers. Thus, for example, a subscriber living in Richardson may only have access to the Richardson modem bank. If the subscriber is traveling away from Richardson and desires to access its Internet service provider, he or she may have to dial long distance into the Richardson modem bank.
Traveling subscribers may also be given access to his or her Internet service providers via a toll free number (e.g., 800, 888, etc.). However, while the subscriber does not pay telephone network toll charges for the call, he or she pays the Internet service provider based upon his or her usage. Thus, the user, in effect, pays for the toll charges via the usage fee. However, this transaction provides little or no benefit to the Internet service provider since it must pay telephone network toll charges to the telephone company.
Calls made by subscribers to the toll free number are routed to a central modem bank that services the calls for the Internet session. For the duration of the call, the telephone network must provide access to the ISP, the call consuming valuable resources of the telephone network. Because Internet sessions typically last longer then a typical voice call, the telephone network must service the calls for a longer period of time which places additional burden on the telephone network.
Thus, there exists a need in the art for a system and related operations in which Internet session calls routed within a telephone network consume fewer resources of the telephone network and less adversely affect operation of the telephone network.
Thus, to overcome the shortcomings of the prior operations, a telephone network constructed according to the present invention includes call redirection functions that redirect calls intended for a toll-free-number or central number of an Internet Service Provider (ISP) to one of a plurality of available Internet Protocol (IP) gateways operated by the ISP. In performing the call redirection, various telephone network components and/or ISP components may be employed.
In a first embodiment, a call is received by the telephone network at an originating switch from a subscriber""s terminal with a toll-free-number or a central number (TFN) for his or her ISP. The originating switch interacts with a coupled service switching point (SSP) of the signaling network, requesting a number lookup for the DN corresponding to the TFN. The signaling network responds with the DN and the call is routed via the signaling network to a destination switch corresponding to the DN.
The destination switch (or coupled SSP) however, instead of completing the call, redirects the call to a new IP gateway. In redirecting the call, the destination switch responds to the new call request with a release message that includes a cause indication, the new called number (CLD) of the new IP gateway and the IP address for the subscriber to use with the IP gateway. The telephone network then releases the call back towards the originating switch for redirection. The originating switch, or some other switch on the route from the originating switch to the destination switch, recognizes the release-and-link call and processes it accordingly. The switch that processes the request delivers the call to the new IP gateway. The IP gateway may be configured to utilize the IP address provided, or may dynamically assign an IP address for the subsequent session. The Internet session is then set up and serviced between the IP gateway and the subscriber""s terminal.
In a second embodiment of the present invention, the call is first routed to a PBX operated by the ISP and the PBX redirects the call to a new IP gateway instead of the destination switch. The PBX then participates in selecting the new IP gateway, in selecting the IP address and in releasing the call from the destination switch.
In a third embodiment, the signaling network itself redirects the call to a new IP gateway. In such case one or more signaling network elements operate to redirect the call prior to its being routed to the destination switch. Such redirection may be performed when a database lookup is initially performed using the TFN. In such case, the database response returns a redirection message that includes a cause indication, the CLD and an IP address to use in the Internet session.
The call redirection may be static or may be dynamic. In static call redirection, all calls are redirected to a single IP gateway. In dynamic call redirection, one of a plurality of available IP gateways is selected based upon operating conditions. In making such selection, IP gateway loading, IP gateway availability, telephone network loading, telephone network availability and telephone network routing costs are considered.
Moreover, other aspects of the present invention will become apparent with further reference to the drawings and specification which follow.